The subject matter herein relates generally to crimping apparatus, and more particularly to crimp quality monitoring systems for crimping apparatus.
Electrical terminals are typically crimped onto wires by a crimping apparatus to form a lead. The crimping apparatus has crimp tooling made up of a first part mounted to a base for supporting the electrical terminal and a second part mounted to a ram that is movable toward and away from the base for effecting the crimp. In operation, the terminal is placed on the first part of the crimp tooling, and an end of a wire is inserted into the ferrule or barrel of the terminal. The ram is caused to move toward the base through a crimp stroke, thereby crimping the terminal onto the wire.
It is desirable to, and systems have been developed that, monitor the quality of the crimp. When a defective crimp is detected, the lead is discarded. Some known crimp quality monitoring systems measure crimp quality by measuring crimp height. Ordinarily, if a terminal is not crimped to the correct crimp height for the particular terminal and wire combination, an unsatisfactory crimp connection will result. However, many unsatisfactorily crimp connections will, nevertheless, exhibit a “correct” crimp height. As such, systems that monitor crimp quality based on crimp height may pass defective leads from the crimping apparatus. Additionally, a crimp height variance or other physical variation in the crimped terminal is not, in and of itself, the cause of a defective crimp connection, but rather, may be indicative of another factor which causes the poor connection. Such factors include using the wrong terminal or wire size, missing strands of wire, short brush, insulation in the crimp, abnormal position of the terminal, wrong wire type, incorrect stripping of insulation, and the like. Since such defective crimp connections frequently have the appearance of high-quality crimp connections, it is difficult to identify these defects in order that timely corrective action may be taken.
Other known crimp quality monitoring systems detect a defectively crimped terminal by analyzing the crimping forces imposed on the terminal during the actual crimping operation. For example, the systems collect force and displacement data during the crimp stroke and compare that data with normalized data collected from known good crimps during a learning phase. Such comparison is utilized to determine whether a particular crimp meets acceptable standards. However, crimp quality monitoring systems that monitor crimp quality based on force profiles are not without problems. The systems are inaccurate at measuring certain types of defective crimps. For example, the systems are susceptible to incorrectly identifying crimps having insulation in the barrel as being good crimps. The systems also are susceptible to falsely identifying some good crimps as being defective.
A need remains for a crimp quality monitoring system that may be used to accurately identify crimp defects. A need remains for a crimp quality monitoring system that may be used to identify the particular defect with the crimp.